Apparatus for resizing pistons



Nov. 18, 1930. A H. SHARP 1,782,011

- APPARATUS FOR RESIZING PISTONS il y 15, 1926 2 Sheets She'et 1 \N N N\\ e. I s N -r N 01 g N Fin- Nov. 18, 1930. F. H. SHARP APPARATLQ FOR RESIZING PISTONS Filed July 15. 1926 2 shun-spent 2 Patented Nov. 18, 1930 UNITED STATES FRED H. SHARP, onsAIjinA, K nsAs APPARATUS non sesam 'r'rs'rons Application filed July 15,

The present invention relates to means for increasing the size or diameter of pistonsand like articles, and is particularly intended for enlarging or increasing the diameter of pistons that have become worn. The object is to provide means whereby such pistons can be brought to proper diameter with ease and expedition and at relatively small cost, thus materially increasing thelifeof such articles.

In the accompanying drawings Figure 1 is a side elevation of the novel implement by means of which the process can be carried out,

Figure 2 is a longitudinal sectional View therethrough showing a-piston in place,

Figure 3 is a horizontal sectional view on the line 5-8 of Figure 2, p Figure 4 is a view in elevation of a piston that can be treated, Figure 5 is a detail perspective view of the piston expanding wedge.

In the embodiment disclosed, metal sleeve '6 is employed, that is longitudinally slitted as shown at 7, and is thus expansible and contractile This sleeve is preferably provided on one side with a lug 8 carrying an outstanding handle 9. The sleeve is furthermore provided on opposite sides of the slit 7 with outstanding lugs 10 and 11. Through one of these lugs extends a rotatable contracting 1 stem 12 that is threaded, as shown at 13 in the other lug 11. The stem preferably has a winged head 14:, by which it can be readily turned. Through the other lug 11 is threaded an expanding screw 15 that bears against the lug 10 and is also provided with a winged head 16. It will thusbe evident that by manipulating the screws 12 and 15, the sleeve can be expanded or contracted as desired. 1

F ulcrumed on the stem 12 is a hand lever 17, bowed, as illustrated at 18, so that the screw 15 will not interfere with its inoveinent. Adjacent to the fulcrum, the lever is of an inwardly pointed wedge, which wedge is adapted to move through the slit 7 of the Figure 2. The article to be treated is shown provided with a bill 19 that is in the form 1926. serial N'0.122}714=.

int-he for'm of a Well known type of piston 20 for'an internal combustion engine. This piston isprovided with alongitudinal slot 21. {n the present ,embodimentthe slot ex tends diagonally tothe longitudinal'axisof the piston; in using this device, and assuming that it is desired, to increase the diameter ofa worn piston, as 20, they internaldiameter. of the sleeve 6 is first set tora diameter greater than thatdesired for the said pist0n-20.--"The piston 2,0 is then iheated, which will 1 expand-it to a certain extent, but less than the internal diameterof the sleeve." [After being'heated,

the piston is introduced into the sleeve with the central portion of the slot 21 in line with-the central portion of the slit. 7 of the sleeve 3 6. The 1 lever-.17; is then moved to a position tocarrythe wedge 19 into the central portioncfthe slot2l, whereby the heatedpia ton is expanded to the diameter of thesleeve, as illustrated in Figures 2, and-3. The sleeve 1 with the mechanically expanded piston is then plunged in "water or: oil and-thereby cooled, which causes the piston. to shrink Sllb, stantially-to the desired diameter. The piston is then removed from the sleeve-and; will i be atsubstantially the; desired diameter; y i 'As anvv exampla it has been found practical to expand a worn piston .030, of an inch; As-L suming that it is necessary to: enlarge. the piston to .005 ofan inchoversize, the-sleeve should then beset by the use of suitable micrometers-at 035 offlan inch. The piston is then 'hea-tedvuntil *it has expanded to the extent of .030 of an inch, which expansion,

when} heating, can; be readily deter-mined iby the use of micrometers... When this heat expansion has been reached, the piston, while thus heatedfis inserted in ithe'sleeve that has already been set. atv .035 of an inch. The wedge is then inserted in the slot in.the piston, andfthe piston mechanically expanded thereby until-Hit snugly fits in the sleeve. This enlarges the piston tothe extent of .005 of an inch abovefthe heat expansion. :The cylinder with the-piston thus inserted and Tmechanically expanded is then submerged v in water or oil, and thereby cooled. This causes shrinkage of the piston to .005 of an inch larger than in the beginning, as a contraction of .030 has taken place in the process of cooling. It has been formd desirable that the wedge 19, when being inserted in the slot,

moves both inward and longitudinally at the same time, this causing a more even expan s1on. 7

From the foregoing, it is thought that the construction, operation and many advantages of the herein described invention will be apparent to those skilled in the art, without further description, and it will be understood that various changes in thesize, shape, proportion and minor details of construction, may be resorted'to without departing from the spirit or sacrificing any of the advantages of the invention.

What I claim, is: i

I 1. A piston sizing device comprising a slitted piston-encircling sleeve, means connecting the portions on opposite sides of the slit for expanding and contracting the sleeve, and a piston expandingwedge that passes through the slit of the sleeve.

slitted piston-encircling sleeve, means connecting the portions on opposite sides of the slit for expanding and contracting thesleeve,"

and a piston expanding-Wedge that passes through the slit of'the sleeve and is mounted on saidexpanding and contracting means.

3. A piston sizing device comprising a slitted piston-encircling "sleeve having outstanding lugs on opposite sides of its slit,

an expanding screw on one lug bearing against the other lug, 'a contracting screw threaded on one lug and bearing against the other lug, and a lever fulcrumed on 7 one of the screws and having awedge that passes through the slit.

4. In combination, a sleeve having walls and of a diameter to encircle a heated engine piston and confine it to a predetermined diameter while maintaining its external 'contour unchanged, said walls of the s'leeve'haw ing an opening, and-means entering laterally through the opening in the walls of the sleeve:

and adapted to engage a slot in a piston placed within the sleeve to expand said cyl-x inder to the diameter determined upon by the sleeve. v

5. In combination, a split expansible and contractile sleeve of a diameter to encircle a heated engine piston andconfine it to a predetermined diameter while maintaining its.

external contour unchanged, and means passing through the split of the sleeve and adapted to engage a slot. in a pistonplaced within the sleeve to expand said cylinder to the diameter determined by the sleeve,"

In testimony whereof, I aiiix my 's1gnature. FRED SHARP.

2. A piston sizing device comprising a 

